The present invention relates to a system for automatically logging the interaction between different objects, and for using this logged information in order to generate detailed reports, studies, and similar information. More particularly, the invention relates to a time and accounting system wherein the interaction between objects, at least one of which is moveable, is automatically and accurately recorded, thereby allowing detailed time studies, reports, billing statements, and the like to be quickly and accurately prepared.
Numerous methods have been used in the past for keeping track of the interactions that occur between two groups of objects, at least one group of which regularly moves relative to the others. One of the most common applications of such systems to date relates to the field of personnel time, care, and accounting systems. Hospitals, prisons, schools, factories, and other custodial institutions are the types of facilities where accurate records are often needed to indicate which personnel have come in contact with other personnel or objects during a specified period of time. In a hospital or health care facility, for example, accurate records must be maintained indicating when and for how long specified hospital employees, such as doctors or nurses, have come in contact with individual patients. Further, in order to operate such facilities efficiently, and thereby reduce operating costs, it is often necessary to perform time studies and the like to evaluate the most efficient use of the available personnel. Moreover, while many employees in such custodial facilities are typically paid on the basis of the number of hours worked, it is sometimes preferred to adjust wages based on the actual performance of the employee, e.g., where the employee has been within the facility, and/or how many specified contacts have been made during a given time period with other objects, patients, students, or the like.
Heretofore, such time care and accounting functions have largely been carried out manually. That is, a written log is maintained at an appropriate location and a written entry is manually made therein to indicate that a certain activity has occurred. The log entries must then be analyzed and sorted as required in order to reach the desired end result--a report, billing statement, paycheck, etc.
While computers have been used extensively in recent years to help analyze this kind of log-entry type data, the data must still typically be manually entered into the computer system. Manual log entries, whether to initially record the particular event, and/or to enter the logged event into a computer system, are undesirable because they are prone to error and they consume valuable time.
Some attempts have been made in the art to automatically generate an identifying log-event signal that is received at a central location, whereat it may be used to signal that the particular event has transpired and/or the location at which the event occurred. For example, in U.S. Pat. No. 3,478,344, there is disclosed a system for monitoring the behavior of supervised individuals. The system includes a portable transceiver worn on the wrist of the supervised individual. This portable transceiver is designed to respond to a interrogating signal received from a central station, and in response to this interrogating signal to transmit a coded signal back to the central station through a directional antenna system. When received at the central location, the signal indicates not only the location of the portable transceiver, but the identity (code) of the source of the signal. In this way, the location or position of a particular supervised individual within a specified boundary area may be monitored without disturbing the individual being watched. Moreover, should the individual wearing the wristband transceiver unit attempt to destroy the unit, self-actuating means are triggered that transmit a higher power signal back to the central station, thereby alerting the central station of the attempted destruction of the signal source.
Unfortunately, the system disclosed in U.S. Pat. No. 3,478,344 only gives an indication of the location of the supervised individual and the occurrence of a single event (attempted destruction of the device). Further, location information is only sent through the use of a directional antenna system, which requires that specialized antennas be strategically placed throughout the supervised area. Also, the wrist transceiver unit requires a rather cumbersome battery pack, worn on the belt on the supervised individual, in order to have power to operate. The device could thereby be easily rendered inoperable by merely disconnecting the power source from the transceiver (e.g., by cutting the wires). Such a system is, of course, ill suited for a hospital, health-care, or similar custodial facility because of the high power radiation signals that may be emitted from the device. Radiation signals in a hospital environment could easily interfer with sensitive monitoring equipment or could even be a hazard to the health of some of the patients (e.g., a patient using a pace maker).
In U.S. Pat. No. 4,347,501, an alarm signalling system is disclosed for use in hospitals, prisons, and similar custodial institutions. According to its teachings, an alarm signalling device--a portable unit that is easily carried in the pocket of a supervised individual--transmits an alarm signal whenever it is manually triggered by the person using the device. Each room or zone of the building or enclosed area where the supervised individuals are housed has a room code associated therewith. The alarm signalling device is adapted to have the room code set therein (through inductive transmission) whenever the device is carried into a given room or area. The set room code is automatically changed when the alarm sending device is carried from one room or location to another. When the manual alarm button is activated, the latest stored room code is sent by radio transmission to a central alarm receiver, where the information can be acted upon to get the needed assistance to the identified room or location as soon as possible.
While the system disclosed in U.S. Pat. No. 4,347,501 offers the advantage of a small portable unit that can have a single location code stored therein, the system must be manually activated before the room or location code may be acted upon. Further, the system does not provide any capability for logging a history of all the rooms or locations in which the unit has been carried over a period of time. That is, the device (as an alarm unit) is only concerned with the present, not the past; and to recreate the past, some means would have to be used to transmit the previous location code back to the central station whenever a new code was entered therein. This would require much more complex circuitry, especially at the central receiving station where the possiblity of receiving two or more alarm signals simultaneously from different portable units would have to be provided for. Such provisions (for handling two or more signals simultaneously) typically include using different radio transmission frequencies for each portable unit, including some complex buffering and interlocks schemes so that the information could eventually be combined, analyzed, and acted upon. As already mentioned, in a hospital or similar sensitive environment, it is generally preferable to minimize the use of radio transmission (radiation). If such radiation must be used, power levels must be kept low--meaning that transmission distances must be kept extremely short--and only a very small number of non-interferring frequencies should be used.